Radiotelephones, while in an idle or standby mode, must constantly monitor a continuous stream of data messages that are sent by the base station. One of these data message streams is on the forward control channel. The format of these messages is shown in FIG. 1 and is explained in more detail in Electronic Industries Association (EIA) 553 cellular system specification at section 3.7.
The radiotelephone uses the dotting word (101), the first word of the message, to synchronize the radiotelephone hardware to the clock of the data message. The synchronization word (102) indicates the present location in the data stream to the radiotelephone and that the data sequence is about to start. Repeat words A and B (103 and 104) are each forty bit words, the content and format of which are defined in EIA 553, and each is repeated five times in the message as illustrated. The radiotelephone receives both of these words but only processes one of them. Which one the radiotelephone processes is determined by the least significant digit of the radiotelephone's telephone number. If the telephone number is even, word A is processed; otherwise word B is processed. In order to receive and process these words, the radiotelephone's receiver must be on and drawing power the entire time, thereby reducing the time a portable, battery-powered radiotelephone can be used for communication. There is a resulting need for a way to reduce the time that the radiotelephone's receiver remains on during the idle mode, thus reducing power consumption, while still receiving the necessary information from the base station.